I think that should just be called "." (without the quotes) XD
You could make it happen at a 25% chance per battle or something. lol
Nah, Rahel is level headed she isn't psychotic. She would have to be manipulated or feel threatened by her teammates. Now that I think about it, she'd really only turn if the enemy captured her and tortured her or otherwise manipulated her into joining them. Such as the granting her the ability to talk to her lost love as their demonstration of Yawah's power. (Ex's are really good at screwing up a good thing >.< ) Though it doesn't seem like they're too much into conversion. Reminds me a lot of the Ori from Stargate SG1.
Let's do a break down of the team that we have actually met.
Griffin: This guy broke you out of prison just because he's your friend. He'll be loyal to the end.
Arman: He's secretive, but he needs a home, a family, and within your team he has that. How many guards did he stand up with alone just so you can rescue your parents? He ain't going anywhere.
Set: this adorable little guy will follow you like a love-sick puppy dog. Sure he has potential to go berserk and mass murder an entire town because he just bottles up all his emotions, but he's having the time of his life, like Arman he's all ways been searching for friends and the bond he has with the team is unbreakable.
Luca: A ghost lady that has a fairly remarkable memory for a ghost, but still doesn't know much about her past. She'll be loyal until her dept to you is repaid, or she forgets you're her friend. Keep in mind she has trouble remembering her own name. She could be easily tricked into thinking you're the bad guy.
Malis: she's there for the money. And with the Cult she's losing business. She's pretty loyal to you, and even though she likely enjoys killing all the fleshlings with you, so far all she sees in you is a few gold pieces. She likely won't turn on you but will probably leave your party if a more profitable business venture is available.
Rahel: She's sweet but damaged. She likes to appear hard but definitively has a soft spot. And with the death of her bf that small mark on her has turned into a gaping wound. No matter what, if she had the chance to get back that guy she would take it. Although she would probably initially refuse if the Cult offered, she would all ways have it on her mind. As soon as your little party with her goes sour she'll start to think and fantasize about it. She would start thinking "maybe everything will be all right if I convert... Perhaps I can request that they leave my friends alone..." and so on. Once in the cult she could be brainwashed into seeing how you guys are in the wrong. She may even try to stop you, which would end violently. She's loyal to her heart.